Appearance

Leonurus cardiaca is a perennial herbaceous plant is 2-5 ft (0.6-1.5 m) tall. The plant generally has few branches. The square stems are ribbed and somewhat pubescent. Stems begin erect but tend to sprawl as they mature. The root system is made up of both shallow fibrous roots and rhizomes. It is native from temperate Russia to central Asia. It has been cultivated in Europe for a many decades.

Foliage

The opposite leaves vary in size and shape. Leaves have long petioles and are slightly pubescent. Leaves become smaller and less lobed as they rise up the stem. The base of each leaf is somewhat wedge-shaped.

Flowers

Flowers are sessile and surround the stem in the leaf axils. Flowers are tubular flower with a white to pink corolla and long white hairs. There are usually purple dots on the lower lip and near the throat of the corolla. Flowers bloom for about 2 months during the summer.

Fruit

Fruits reddish brown to brown three sided nutlets. Each flower produces four nutlets.

Ecological Threat

L. cardiaca occurs in open disturbed woodlands, areas along woodland paths, woodland edges and thickets, edges of degraded wetlands, edges of yards underneath trees, and partially shaded fence rows. It can also invade natural woodland areas. This plant is still sold by commercial nurseries as a medicinal herb.

Selected Images

Maps

Invasive Listing Sources

• City of Ann Arbor Michigan Parks and Recreation
• Invasive Plant Association of Wisconsin
• John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• WeedUS - Database of Plants Invading Natural Areas in the United States

References